Re: web-mode.el

[Dmitry Gutov <dgutov@yandex.ru>]

On 19.06.2012 7:09, Stefan Monnier wrote:
>> It occurs to me that, once the supported interface is established,
>> introducing new syntax-table value becomes not strictly necessary because,
>> for example, a version of Lennart's `with-chunks' macro can be implemented
>> in Lisp by applying whitespace or comment-starter/ender syntax to foreign
>> chunks around the body calls (idea from mmm-noweb).
>> Is that right?
>
> That's right as long as you're willing to dynamically modify the buffer
> (with syntax-table text-properties) every time you move from one chunk
> to another.

Or just every time I want to indent a line, instead. And if I always use 
`narrow-to-region' before performing indentation within a submode, the 
syntax-table text property (unless it's 'whitespace') isn't going to 
affect the result, so I might as well assign text properties only once 
when the buffer is parsed for chunks, "commenting out" the submodes.

> If you have many chunks, that can be a problem.  This can happen if you
> push the idea of multi-major-mode a bit further and consider for example
> that comments and strings are really "text-mode chunks" embedded in
> "some other mode chunks".

Yes, but what follows is defining the supported interface and patching 
existing packages becomes first priority, and implementing low-level 
support in C code - only second, which means more time to get the latter 
right.

For example, I'd like to see a use case for handling submode regions of 
the same mode as though they're contiguous (as oppsed to isolated), in 
the context of `syntax-ppss'. If there isn't, it might simplify the 
implementation.

On 19.06.2012 14:39, Lennart Borgman wrote:
 > My idea with (with-chunks chunk-table ...) that chunk-table contains
 > this information instead. Then it can be cashed by the multi major
 > mode framework.

You might want to consider how syntax-ppss cache works. Since 
text-property change in considered buffer modification, 
`syntax-ppss-flush-cache' will be called from `before-change-functions', 
invalidating the cache entries with positions after the edit position, 
and keeping the ones before it.
With your proposal, it would need to somehow keep track of the 
chunk-table, too.